code: def forward(self, x):
      n, _, h, w = x.shape
      return [
          chainer.Variable(
              _random_array(self.xp, (n, 16, h // 2, w // 2))
          ),
          chainer.Variable(
              _random_array(self.xp, (n, 32, h // 4, w // 4))
          ),
          chainer.Variable(
              _random_array(self.xp, (n, 64, h // 8, w // 8))
          ),
      ]
  
file_path: chainercv/tests/links_tests/model_tests/fpn_tests/test_fpn.py
imports: from __future__ import division
  import numpy
  import unittest
  import chainer
  from chainer import testing
  from chainer.testing import attr
  from chainercv.links.model.fpn import FPN
label_desc: Use image node_id 1 for calling the DummyExtractor obj's underlying member method code with example usage: obj.forward(x) and returns: list